Need step-by-step guide for changing Canister Purge Valve

[prince402]

I just got the 94 EB 4dr 4X2 with 166K miles. Cleared the CEL by finding only one error code for the EGR pressure sensor. I was pleased to find that so easy, just sitting near the top of the engine, DS.

I get a strong gas smell from the cannister vent and figure it is the purge valve solenoid that appears to be behind the mounting plate for the EGR pressure sensor.

There is no error code showing but I still figure that it is the valve. Anyway, I would guess that I could get at it by removing the mounting plate for the above sensor but I would like input from those who have done it on the 94.

BTW, I just ordered this for 23 cents on Amazon: "Ford Explorer & Mazda Navajo Automotive Repair Manual: All Ford Explorer and Mazda Navajo Models 1991 Through 1995 (Hayne's Automotive Repair Manual)" Ahlstrand, Alan; Paperback; $0.23In Stock Sold by: betterworldbooks_

But until it gets here I need guidance on this replacement.

 

[Jason94sport]

Replace the canister 1st. The thing with 2 knob looking things on top of it.
The valve is easy 123, hardest part is getting you fingers in there. They are just hoses that pull off & then the electrical connector.

 

[prince402]

OK, so together with and encouraged by a "123" attitude, I went out to my carport (personal garage) and removed the egr pressure sensor mounting plate (all of one half-inch bolt) and exposed the purge valve. But, all stopped there because I am not sure how to deal with the remaining procedures. Then too keep in mind my hardship of working in a real cold snap here in Fort Lauderdale, fifties at night and low seventies in the day! Also my 23-cent Haynes manual is in the mail and not available, but I want the gas smell to stop now.

Problems stopping me right now:

1. Not enough area is opened up for my nimble fingers. It looks like I would also have to remove the fixture to the right of the sensor plate, the egr valve?, I believe, with some substantial bolting and gasketing to the engine. Even with my fairly good mechanical skills and experience, I would need exact advise on removal and replacement. New gasket? Gasket sealer? ETC. Removing this would allow me to get at the electrical plug for removal and installation. Or is there another way?

2. The T-hose fitting is not connected to the typical black rubber tubing but to shrink-fit hard plastic tubing from the canister and to the engine. How do I free it from the old valve that I am removing? Then how do I hose fit the new one to the hard plastic tubing? We have really well stocked salvage yards here and I got a salvaged valve for $4 with the plug and wiring that allowed me to already verify that this used one works fine. Also with it is one leg of the plastic tubing that I cannot remove by twisting and pulling as with rubber tubing, hence my tubing removal/replacement concern above.

I have a good, trustworthy mechanic who looked up the flat rate on this job; it is 0.9hr which indicates that this is not a real simple job. Since I am guilty to a fault of doing things myself, I still want to finish this job and need help here. Salvaging was to only cut the wiring since the top of the engine was already removed. I had previously cleared a code by replacing the egr pressure sensor and that's an example of a 0.1 hr easy picking job.

My 1994 EB 4dr 4X2 is a Florida car with no rust at all and with a like new original paint/clearcoat job. My first tank of gas driving in urban local traffic was a crummy 14.5mpg. I was hoping the new egr pressure sensor would help but the gas gage needle is still dropping too fast. Now I am hoping that a working purge valve will help with the mpg since all of that gas I am now smelling will be used for propulsion.

Here is a slideshow illustrating the above: http://s629.photobucket.com/albums/uu19/princeinflorida/ExplorerForumPurgeValve/?albumview=slideshow

And, yes, I need to find a ds EB rocker panel extension and a matching Ford wheel center. The one missing wheel center is now filled with a Lincoln one that I picked out of the scrap heap at the salvage yard, much better than the empty center.

Thanks in advance and for current interest.

 

[mussey ex]

I used a long pair of forceps (tong like devises) to reach in and grab the hose, and pulled it into a position where I could grab a hold of the valve. It's kinda like a puzzle, pull backwards, pull to the right, twist a little....It will come out.

when you get it, you'll have to twist/turn and pull the hose to get it off the plastic stems, be careful of side pressure, they break somewhat easily.

 

[Jason94sport]

I'm in Boca. If you can't get it let me know next week, I'll do it for you. But I still say it's the canister & not the valve. I replaced 3 of them for the same reasons.

 

[prince402]

Thanks guys for your support and kind offer which boosted my confidence enough for me to get up yesterday morning at 5am and go at it. I did get it done but it took me a few hours. I did not change the canister and the gas vapor smell is gone at the canister stacks. So it appears that just the valve will take care of the gas odor. I'll add a note to this thread if it comes back.

When I started it up, the tail pipe dripped water for about five minutes and then stopped. Whew, I was worried about a blown head-gasket but thankfully no! I'm guessing that without positive venting that the canister accumulated water. The ethanol in our gas absorbs water and that may be why.

A very pleasant surprise is that the engine now idles perfectly smoothly, very noticeably better than before the repair. I had also experienced perceptively better idling when I replaced the egr pressure sensor a few days ago. So these two repairs were well worth it. I had a KOEO code for the sensor but not the valve.

Here are some tips I learned that I am pleased to pass on to this thread.

Get visibility and access to the engine vapor intake hose barb by removing the triangular cowling at the front top right of the engine (it has the semi-circular cutout for the large air duct) by removing the two 8mm bolts. There is also some visibility and access looking down between the AC compressor and the engine. This is the only rubber engine side connection commonly found in the original Ford configuration. All of the other tubing to the valve and on to the canister is rigid plastic that cannot be pulled from the valve. Then at the canister end there is a rubber fitting at the hose barb on the canister. The rubber end fittings at the engine and the canister allow it to be removed as one piece or broken for easier removal.

Having access to the engine hose barb and rubber fitting allowed me to deliberately re-rout the replacement valve tubing, fixing the replacement valve onto the canister where it can be readily and easily changed in the future. I had salvaged the valve together with its electrical plug and as much wiring as I could get. I crimped two spade terminals onto some lamp wire and plugged them into the original plug terminal still on top of the engine behind the egr pressure sensor. Then I spliced the lamp wire with wire nuts onto the salvaged plug/pigtail out at the canister where the valve is now mounted.

I've learned to salvage electrical/pneumatic parts with as much tubing and wiring that I can get for the part. This is another advantage of a salvaged part over a new one in addition to the typical 75% to 90% discount.

 

[Jason94sport]

Glad it worked out. I'm terrible at explaining how to change it, I just do it by feel. Once I'm in there I remember. Yeah keep an eye out with the canister. They are pretty easy to find & replace if you have too.

Question where did you get the part? I'm looking for a sway bar bracket. The 2 yards close to me do not have anything.

 

[prince402]

http://www.you-pull-it.com/ (see the price list) and there a few others around Ft. Laud. If you need a hand with it, let me know, and I may be able to go with you. The alternative is to call one of the non-self-service yards where you can pick it up at the counter and pay more.

I forgot to include above in my previous post to disconnect the engine end of the air duct under the removed cowling (right front top of engine) for physical access to the engine hose barb. Just set it on top of the engine and you can reach into the engine hose barb connection.

I've added three pictures at the beginning of the slideshow to show the cowling and the engine hose barb and vapor hose coupling.
Here it is again: http://s629.photobucket.com/albums/uu19/princeinflorida/ExplorerForumPurgeValve/?albumview=slideshow

I've now revised my worst placed part designation on the 94 Explorer from the cigarette lighter inside the ashtray (instead of on the dashboard) to the purge valve being where it is as discussed above!

 

[OneofMany]

I have the same smell and bad fuel mileage. Plus my canister has the tops missing that look like mushrooms. the purge valve you show in picture 6 with the t connector isnt connected to anything. also the aluminum valve mounted on the engine in pic 3 and 4 had the front port marked 'ref' not connected to anything. i ran a hose down the the egr hose that has a hose runnin to the other port on that same valve because i didnt find anything else that seemed likely to have been connected...help!? Im not a Ford guy apart from the 70's stuff and have no manuals on this piece of work

 

[OneofMany]

how can you test the vapor canister and purge valve? if the canister is full because the purge valve isnt working, wouldnt it empty when the purge valve is fixed?

 

[prince402]

It's been a year since I posted the above but I went out just now and took two more pix that will now be the first two of the above slideshow.

First Pic: This is the egr pressure sensor. The hose barb marked REF (front one) connects to the top hose barb in the egr tube (egr tube covered with braid) and the back one connects to the bottom hose barb in the egr tube. This is shown in this new pic. This should allow you to get it connected correctly. My bad one showed an error code but the purge valve did not.

Second Pic: Carbon canister on right, brake fluid reservoir back center, and the replacement purge solenoid in its relocated position connected directly to the canister. The tubing on the left barb leads to the intake barb on the engine clearly shown in the fourth picture. The original solenoid was plugged into two spade terminals way back in the recesses of the top of the engine and connected to the intake barb via a rigid plastic tube not used in this new configuration. A 12V extension line fitted with female spade connectors goes between the two spade connectors back in that recessed place to the new position next to the cannister. The line can be seen in the fourth pic. The relocated position allows easy replacement in the future.

You can check the purge valve when removed by blowing through the tubing with 12V applied and not applied. When applied you should be able to blow through it (it is opened by the 12V energy).

I don't know how important the mushroom caps are. A close examination should tell you that, otherwise just get a salvaged replacement. To my knowledge these canisters last a long time. The caps probably keep out contamination including water.

The canister holds gas fumes via the charcoal and empties as I have described above including some water likely held by the alcohol. See my description above when I started it up after replacement.

Hope this helps. Had to refresh myself on all this. I like to return info in appreciation of all the info I have gotten in this forum.

BTW: My mpg didn't increase much (if any) and I still get between 15 to 18 mpg, around town and on long trips. I may have gotten 18.9 mpg once!!!!